This disclosure relates to a fluid element, such as an impeller, having front and rear shrouds integral with the blades.
One type of fluid machine, such as a turbomachine pump, has a radial impeller with front and rear shrouds integral with the impeller blades to provide an interior pumping surface. The blades are circumferentially arranged to provide circumferentially spaced exits about the impeller outer perimeter. Trailing ends of the blades extend to the impeller outer perimeter.
The front and rear shrouds respectively include first and second perimeter surfaces at the impeller outer perimeter. Typically the first and second perimeter surfaces have thicknesses that are the same as one another. Some impellers have a thick rear shroud that provides a second perimeter surface that is thicker than the first perimeter surface. Other impellers have the trailing edges and the immediately surrounding portions of the first and second perimeter surfaces recessed radially inwardly from the impeller outer perimeter to accommodate a balance piston.
Like numerals in the Figures indicate like elements.